Many things the internet will tell you exist in Japan are still not the norm around here. I've been here a decade and have come across traffic warning signs for deer, cattle, tanuki (raccoon dogs) and in the mountains for bears, never for cats. So these are irregular signs. The one on the left strikes me as one given special dispensation for by the authorities to prevent accidents on a public road, maybe even in just one village that's overrun with ferrals. The writing underneath just reads look out for animals. The one on the right looks to me like it could just be on private property somewhere.
Compare: In America they have presidents carved into mountains! Factually not incorrect but misleading, as it's just four of them and they're all in the same place.
